JPH04177478A - Fingerprint collation device - Google Patents

Abstract

PURPOSE:To perform the identification of an individual quickly and with high reliability without using an uncertain element such as a key or a password number, etc., by collating a registered one finger or all fingers with an input fingerprint. CONSTITUTION:An image input control part 12 checks the temporal gradation change of plural picture elements at prescribed positions in an image fetched at need, and detects the placement of a fingerprint, and also, automatically extracts a fingerprint image when the gradation value of the picture element exceeds a threshold value. A two-dimensional quantization image obtained in such way is stored in image memory 13. A collation processing part 18 reads out minutiae lists L1, L2,..., Ln stored in a file 20 one by one in sequence of storage, and stores them in working memory 17, and performs coincidence collation processing with an extracted fingerprint image in the image memory 13.

Description

TECHNICAL FIELD The present invention relates to a fingerprint matching device, and more particularly to a fingerprint matching device that identifies an input fingerprint and a registered fingerprint by determining their identity based on their pattern characteristics.

Conventional systems that use fingerprints to identify individuals have extremely high reliability due to the characteristics of fingerprints that are "unique for everyone" and "unchangeable throughout life." An automatic fingerprint verification device has already been proposed, and there are many techniques such as those disclosed in Japanese Patent Laid-Open No. 60-29875 and Japanese Patent Laid-Open No. 60-221881.

On the other hand, with the rapid progress of electronic engineering in recent years, there is a need for vehicle theft prevention IJ that makes full use of computer technology, and personal identification for extremely limited people, such as locks for residential doors. gender is on the rise.

Traditionally, this has been done using keys, PIN numbers, etc.
Its effectiveness is lost due to theft, loss, forgetting, etc., and therefore it must be said that its reliability is low.

Purpose of the Invention Therefore, the present invention has been made to solve the drawbacks of the prior art, and its purpose is to identify individuals using their fingerprints without using uncertain elements such as keys or PIN numbers. It is an object of the present invention to provide a fingerprint verification device that allows identification to be performed quickly and with high reliability.

Structure of the Invention According to the present invention, a fingerprint matching method compares an input fingerprint image and a registered fingerprint image and determines whether the input fingerprint image matches the registered fingerprint image based on the characteristics of these two fingerprint images. The device includes a means for collecting a fingerprint image of a finger placed on a transparent body and outputting it as two-dimensional quantized image data, and a means for collecting a fingerprint image of a finger placed on a transparent surface and outputting it as two-dimensional quantized image data, and the position, pattern direction, and neighboring minutiae of a minutiae extracted from the registered fingerprint. A file storing a feature list registered in advance and the feature list are sequentially read out, and the feature point and its vicinity are determined from the quantized image data based on the position and pattern direction of each feature point in the feature list. means for detecting and confirming feature points and determining whether the number of confirmed feature points exceeds a predetermined threshold; and determining that the two images match when it is determined that the number of confirmed feature points exceeds the threshold; and means for instructing to repeat the above process for the next feature list stored in the file when it is determined that the threshold value is not exceeded. A device is obtained.

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, the present embodiment is a fingerprint matching device that determines whether pattern characteristics match an input fingerprint image and a registered fingerprint image. This device includes a fingerprint image input unit 10 that collects a fingerprint image of a placed fingerprint and converts it photoelectrically, and a photoelectric conversion signal that is
an A/D converter 11 that converts into dimensional quantized image data;
An image input control unit 12 that detects the placement position of a collected image and then performs image collection, an image memory 13 that stores two-dimensional quantized image data, and feature points extracted from registered fingerprints (hereinafter referred to as minutiae). A file 20 that stores a mechanical list in which the position, pattern direction, and nearby feature points of the image (called "1") are registered; an output section 19 that outputs matching results and various messages; and image data in the image memory 13.
A collation processing unit]8 that sequentially performs collation with all mechanical lists stored in the file 21.

The collation processing unit 18 has an external interface 14 that inputs data from the image memory 13 and the file 20 and outputs it to the output unit 19, a working memory 17 that stores the manual list from the file 20, and a program that stores the program. It is composed of a memory 16 and a central processing unit 15 that is controlled by a program.

Regarding the fingerprint input unit 10, using optical boundary conditions due to light from a light source with respect to a finger placed on a transparent body,
ITV (Industrial Televis)
A device that inputs a photoelectrically converted image of a fingerprint pattern using a photographing device such as ion).
There are devices described in No. 0 and Japanese Unexamined Patent Publication No. 54-85600, which can be used.

Next, the image input control unit 12 checks temporal changes in density of a plurality of pixels at predetermined positions in the captured image as needed, detects placement of a fingerprint, and determines whether the density value of the pixel is equal to or higher than a threshold value. Automatically collects fingerprint images when The two-dimensional quantized image thus obtained is stored in the image memory 13.

The collation processing unit 18 reads out manualists LL, L2゜, . . . , Ln stored in the file 20 as shown in FIG. Performs matching processing with the image.

FIGS. 2(a) and 2(b) show the fingerprint pattern and manualist in this embodiment. In Fig. 2, the fingerprint features are determined by the position of minutiae Mi (Xi, Yi
), pattern direction Di, neighborhood minutia m, ', m old 2
．． m, 3. This is a list representation of each minutiae Mj that exists in a fingerprint, with m,' as a unit.

The information on the nearby minutiae m,'' is the position and direction of the minutiae ml'.

FIG. 3 shows an example in which the minutiae list is registered as a file, and L+ is a file in which all the minutiae of a certain person's fingerprints are registered together.

Detailed definitions of these mechanicalists and methods for extracting them are described in Japanese Patent Application Laid-open No. 138174/1982, so detailed explanation thereof will be omitted here.

The matching processing unit 18, as shown in FIG.
Processing is performed to accurately match the grayscale fingerprint image 30 stored in file 20 with the minutiae (for example, 31) among one or more minutialists stored in file 20. If there is a correspondence, it is considered a match; if not, it is considered a mismatch, and if the number of matches exceeds a threshold, the matching is completed. If the number of matches does not reach the threshold, all manualists L! stored in the file 20! By repeating the same verification process, individuals can be identified for various purposes.

The minutiae detection and relation detection used here use the linear scanning method detailed in JP-A-62-144289 and JP-A-62-118488, respectively, and the details thereof are described here. Omitted.

Next, the verification processing procedure in this embodiment will be explained based on the processing flow diagram of FIG. In step 51, as described above, image input processing is performed by examining the temporal change in density of pixels at a predetermined position.

In step 52, the manualists in the file 20 are accessed one by one in the order in which they are stored as shown in FIG. 3 and stored in the working memory 17.

In step 53, the above-mentioned matching process based on minutiae detection is performed. In step 54, if the number of feature points confirmed on the input fingerprint among the feature points in the manualist is equal to or greater than the threshold value 01, it is determined that the input fingerprint and the registered fingerprint match, and in step 55, The results are displayed.

In step 54, if the number of confirmed feature points in the mechanical list does not reach θ1, it is determined that there is no match, and it is determined in step 56 whether or not the mechanical list remains in the file 20. If there are any remaining manuals, the process returns to step 52, accesses the next manual list, and repeats the matching process in step 53. If there are no remaining manualists, it is assumed that there is no matching fingerprint, and the result of non-matching is displayed in step 55.

In this embodiment, the fingerprint image stored in the image memory 13 is a multivalued image, but a binary image that has been binarized using a known method is stored and that image is processed. However, the essence of the process remains unchanged.

As described in detail, according to the present invention, by comparing one or more registered fingers with the input fingerprint, it is possible to access a specific manualist using a password as in the past. Since this is not necessary, it is possible to obtain a highly reliable personal identification device with excellent operability that does not involve theft or forgetting of the PIN number.

[Brief explanation of the drawing]

Fig. 1 is a system block diagram of an embodiment of the present invention, Fig. 2 (a) is a diagram showing an outline of minutiae, Fig. 2 (b) is a diagram showing a list of the minutiae, and Fig. 3 is storage in a file. A diagram showing the state of the manualist,
FIG. 4 is a diagram showing the state of comparison between the collected fingerprint and the registered fingerprint with the minutiae, and FIG. 5 is a flowchart showing the operation of the embodiment of the present invention. Explanation of symbols of main parts 10... Fingerprint image input section 11... A/D conversion section 12... Image input control section 13... Image memory 15 ... Central processing section 17 ... Working memory 18 ... Verification processing section 19 ... Output section 20 ... File

Claims (1)

[Claims] (1) A fingerprint matching device that compares an input fingerprint image and a registered fingerprint image and determines whether the input fingerprint image matches the registered fingerprint image based on the characteristics of these two fingerprint images, A means for collecting a fingerprint image of a finger placed on a facepiece and outputting it as two-dimensional quantized image data, and a feature list in which positions of feature points, pattern directions, and neighboring feature points extracted from registered fingerprints are registered in advance. A file containing
sequentially reading out the feature list, detecting and confirming the feature point and its neighboring feature points from the quantized image data based on the position and pattern direction of each feature point in the feature list;
means for determining whether the number of confirmed feature points exceeds a predetermined threshold; and means for determining that the two images match when it is determined that the number of feature points exceeds the threshold, and terminating the matching process. and means for instructing to repeat the above process for the next feature list stored in the file when it is determined that the threshold value is not exceeded.